What is a prosthesis? | Trakya Protez Ortez

What does a prosthesis do?

In short: a device takes on some of the tasks of a part that is not there. In the lower limb that is often stance, balance and carrying the step forward. In the upper limb, holding, pushing, leaning and appearance may come first.

A prosthesis is not one solid object. The socket that meets the body, the suspension that keeps it on, a joint when one is needed, the pylon that carries load, and the foot or hand that finishes the job are considered together. Materials and joints change with weight, ground and pace.

The difference from an orthosis, in one line

A prosthesis fills an absence. An orthosis is worn on a limb that remains. If the limb is there and support is the question, the subject is usually an orthosis. If a part is missing, the subject is a prosthesis. Borderline cases need a specialist assessment.

If you are looking for support, see the orthosis

The limb line stops below the knee. Socket, pylon and foot are built into that absence.

Principal groups

Below-knee prosthesis

Transtibial level. When the person’s own knee remains, the prosthesis is built at calf height. The direction of walking depends greatly on that knee, which is why socket comfort is critical.

Above-knee prosthesis

Transfemoral level. The knee becomes part of the system. The knee unit is chosen with safety, sitting, slopes and different walking speeds in mind.

Knee level and foot levels

Knee disarticulation, and foot or partial-foot loss, are separate groups. Remaining length, the surface that bears weight, and the wish for appearance all change the form.

Arm and hand prostheses

Forearm, upper-arm and partial-hand levels belong to the upper limb. A device may be passive, body-powered or responsive to muscle signals. The goal is not the same for everyone.

Appearance and function together

Some people ask first about appearance, others about pace. The two do not have to oppose each other. Priority is set in conversation.

The parts that hold a prosthesis together

01

Socket

The part that fits the body. Weight is met here. A good socket is most of a prosthesis’s comfort.

02

Liner and suspension

The soft interface and the method of holding — pin, vacuum or strap — keep the device in place.

03

Joint

If a knee or elbow is required, the unit is chosen for the person’s balance and everyday ground.

04

Pylon

The structural tube between socket and foot or hand. Height and alignment are set here.

05

Terminal device

A foot below, a hand or hook above. An energy-return foot and a durable everyday foot do not do the same job.

Who is this page for?

A person considering a prosthesis, their family, and a client from another country who wants to understand the process. It does not name the joint that belongs to you. Measurement, the residual limb, general health and goals do that.

Information only. This text does not diagnose, recommend a device or replace treatment. The decision is made with the physician and the prosthetist-orthotist who assess you.

A device that stands in place of a missing part.